Generation and manipulation of bright spatial bound-soliton pairs under the diffusion effect in photovoltaic photorefractive crystals

The generation and propagation characteristics of bright spatial bound-soliton pairs (BSPs) are investigated under the diffusion effect in photovoltaic photorefractive crystals by numerical simulation. The results show that two coherent solitons, one as the signal light and the other as the control light, can form a BSP when the peak intensity of the control light is appropriately selected. Moreover, under the diffusion effect, the BSP experiences a self-bending process during propagating and the center of the BSP moves on a parabolic trajectory. Furthermore, the lateral shift of the BSP at the output face of the crystal can be manipulated by adjusting the peak intensity of the control light. The research results provide a method for the design of all-optical switching and routing based on the manipulation of the lateral position of BSPs.

“Periodic”soliton explosions in a dual-wavelength mode-locked Yb-doped fiber laser

We report the"periodic"soliton explosions induced by intracavity soliton collisions in a dual-wavelength modelocked Yb-doped fiber laser.Owing to the different group velocities of the two wavelengths,the mode-locked solitons centered at different wavelengths would periodically collide with each other.By using the dispersive Fourier transformation technique,it was found that each collision would induce soliton explosions,but none of them would be identical.Therefore,this phenomenon was termed as"periodic"soliton explosions.In addition,the dissipative rogue waves were detected in the dual-wavelength mode-locked state.The experimental results would be fruitful to the communities interested in soliton dynamics and dual-comb lasers.

Graphene-decorated microfiber knot as a broadband resonator for ultrahigh-repetition-rate pulse fiber lasers

Searching for an ultrahigh-repetition-rate pulse on the order of hundreds of gigahertz(GHz) is still a challenging task in the ultrafast laser community. Recently, high-quality silicon/silica-based resonators were exploited to generate a high-repetition-rate pulse based on the filter-driven four-wave mixing effect in fiber lasers. However,despite their great performance, the silicon/silica-based resonators still have some drawbacks, such as single waveband operation and low coupling efficiency between the fiber and resonators. To overcome these drawbacks,herein we proposed an all-fiber broadband resonator fabricated by depositing the graphene onto a microfiber knot. As a proof-of-concept experiment, the graphene-deposited broadband microfiber knot resonator(MKR)was applied to Er-and Yb-doped fiber lasers operating at two different wavebands, respectively, to efficiently generate hundreds-of-GHz-repetition-rate pulses. Such a graphene-deposited broadband MKR could open some new applications in ultrafast laser technology, broadband optical frequency comb generation, and other related fields of photonics.

1.7-μm dissipative soliton Tm-doped fiber laser

We report on the dissipative soliton generation in a 1.7-μm net-normal dispersion Tm-doped fiber laser by nonlinear polarization rotation technique. An intra-cavity bandpass filter was employed to suppress the longwavelength emission, while the cavity dispersion was compensated by a segment of ultrahigh numerical aperture(UHNA4) fiber. The dissipative soliton with a central wavelength of 1746 nm was obtained, covering a spectral range from 1737 nm to 1754 nm. The de-chirped duration and energy of the dissipative soliton were 370 fs and 0.2 nJ, respectively. In addition, the dynamics of multiple dissipative solitons were also investigated. Through optimization of the cavity dispersion, the 50 nm broadband dissipative soliton with de-chirped pulse duration of 230 fs could be achieved. The development of dissipative soliton seed laser represents the first step in achieving the chirped pulse amplification system at the 1.7-μm wave band, which would find potential applications in fields such as biomedical imaging and material processing.

Q-switched mode-locked multimode fiber laser based on a graphene-deposited multimode microfiber

We report Q-switched mode-locked(QML)pulses generation in an Yb-doped multimode fiber(MMF)laser by using a graphene-deposited multimode microfiber(GMM)for the first time,to the best of our knowledge.The single-wavelength QML operation with the central wavelength tunable from 1028.81 nm to 1039.20 nm and the dual-wavelength QML operation with the wavelength spacing tunable from 0.93 nm to 5.79 nm are achieved due to the multimode interference filtering effect induced by the few-mode fiber and MMF structure and the GMM in the cavity.Particularly,in the single-wavelength QML operation,the fifth harmonic is also realized owing to the high nonlinear effect of the GMM.The obtained results indicate that the QML pulses can be generated in the MMF laser,and such a flexible tunable laser has promising applications in optical sensing,measuring,and laser processing.

Few-layer MoS2-deposited microfiber as highly nonlinear photonic device for pulse shaping in a fiber laser [Invited]

Two-dimensional（2D） materials have emerged as attractive mediums for fabricating versatile optoelectronic devices. Recently, few-layer molybdenum disulfide（MoS2）, as a shining 2D material, has been discovered to possess both the saturable absorption effect and large nonlinear refractive index. Herein, taking advantage of the unique nonlinear optical properties of MoS2, we fabricated a highly nonlinear saturable absorption photonic device by depositing the few-layer MoS2 onto the microfiber. With the proposed MoS2 photonic device, apart from the conventional soliton patterns, the mode-locked pulses could be shaped into some new soliton patterns, namely,multiple soliton molecules, localized chaotic multipulses, and double-scale soliton clusters. Our findings indicate that the few-layer MoS2-deposited microfiber could operate as a promising highlynonlinear photonic device for the related nonlinear optics applications.